<!DOCTYPE html>
<html>
  <body />

  <script>
    const video = document.createElement('video');

    async function start() {
      const canvas = document.createElement('canvas');
      canvas.getContext('2d').fillRect(0, 0, canvas.width, canvas.height);
      video.srcObject = canvas.captureStream();
      await video.play();
      await video.requestPictureInPicture();
      return true;
    }
  </script>
</html>
